Six healthful habits that can totally backfire

These six things might sound good for your health, but . . .

You eat clean, work out, meditate and pretty much do all the "right" things. So of course that means you'll be slim, healthy and injury-free, correct? Not so fast. Some seemingly good things actually aren't so great, especially if you go overboard or get into them too quickly. Here are a few times that your best-laid intentions can backfire, and how to find the middle ground.

1. You wouldn't dream of drinking regular soda; it's only diet for you, thank you very much.

Giving up sugary soft drinks sounds like a good plan if you're trying to cut calories. But a study from the University of Texas Health Science Center found that diet soda consumption was actually linked with obesity. What gives? "At zero calories, diet soda will not make you gain weight," says Amy Goodson, sports nutritionist for the Dallas Cowboys. "However, the artificial sweetener in diet soda does not satisfy the body's craving for sugar, and may trigger sugar cravings and can potentially lead to eating more calories from other foods." Swap diet soda for plain or flavored water or add a lemon twist to carbonated water.

2. If a food's not healthy, you're not eating it.

There's nothing wrong with reading labels and buying organic. But if these eating habits become so strict it sacrifices your health or becomes nearly impossible to reasonably maintain, it's time to reassess. "People with orthorexia embrace such a narrow view of their version of healthy eating that they go overboard," says Lisa Ellis, an eating disorders specialist in New York City. Unlike anorexics, orthorexia sufferers are more concerned about the perceived quality, not quantity, of their food. Over time they find their food choices dwindle down drastically, which can lead to nutrient deficiencies. Recovery usually involves professional help from someone who specializes in eating disorders.

3. When milk's not skim, you're not in.

It seems logical to cut out high-fat milk in favor of skim, especially if you're trying to lose weight, but one study found that the full-fat version may be a better bet. Swedish researchers found that people who consumed high-fat milk, butter and cream were less likely to become obese over a 12-year period than those who never or rarely ate high-fat dairy. One possible reason: "Fat sustains you longer, so you're fuller and likely to eat less overall," says Tori Cohen, director of food and nutrition services at Los Robles Hospital in Thousand Oaks, Calif.

4. You throw yourself into Power Yoga with all your, um, power.

Even if you're a seasoned exerciser, diving directly into a challenging yoga class — often called Power Yoga — can cause you to strain muscles. "Power Yoga increases strength, provides a moderate cardio stimulus, and increases flexibility," says Michele Olson, professor of exercise science at Auburn University in Montgomery, Ala. "But, go easy in the early stages. Use blocks and other props. Go slowly and modify poses when necessary. Moves should feel good, not painful," says Olson.

5. You're pretty sure CrossFit was made for you — even though you've never really done it.

The popularity of box jumps — called plyometrics, or jump training — in popular workouts such as CrossFit or bootcamp fitness, has been increasing. Unfortunately, such high-impact moves can be really rough on your tendons, bones and joints, particularly for newbies, says Olson. "Muscles and tendons can only be stretched and shocked so many times before they break down." To stay safe, begin slowly and progressively, working the jumping moves into your routine, says Olson.

6. You stretch so much Gumby would be green(er) with envy.

Like yoga, the slow and relaxing nature of stretching makes it seem like an unlikely high-risk venture, but you can definitely overdo it, says Michael Shepard, an orthopedic surgeon with Hoag Orthopedic Institute in Irvine, Calif. Stretch only after you're warmed up, ideally after your workout. And focus on total body stretches versus individual muscles, suggests Shepard, such as downward dog.